fullstack/hyracks/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/tokenizers/DelimitedUTF8StringBinaryTokenizer.java

/**
 * Copyright 2010-2011 The Regents of the University of California
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on
 * an "AS IS"; BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations under
 * the License.
 * 
 * Author: Alexander Behm <abehm (at) ics.uci.edu>
 */

package edu.uci.ics.hyracks.storage.am.lsm.invertedindex.tokenizers;

import edu.uci.ics.hyracks.data.std.primitive.UTF8StringPointable;

public class DelimitedUTF8StringBinaryTokenizer extends AbstractUTF8StringBinaryTokenizer {

    public DelimitedUTF8StringBinaryTokenizer(boolean ignoreTokenCount, boolean sourceHasTypeTag,
            ITokenFactory tokenFactory) {
        super(ignoreTokenCount, sourceHasTypeTag, tokenFactory);
    }

    @Override
    public boolean hasNext() {
        // skip delimiters
        while (index < length && isSeparator(UTF8StringPointable.charAt(data, index))) {
            index += UTF8StringPointable.charSize(data, index);
        }
        return index < length;
    }

    private boolean isSeparator(char c) {
        return !(Character.isLetterOrDigit(c) || Character.getType(c) == Character.OTHER_LETTER || Character.getType(c) == Character.OTHER_NUMBER);
    }

    @Override
    public void next() {
        tokenLength = 0;
        int currentTokenStart = index;
        while (index < length && !isSeparator(UTF8StringPointable.charAt(data, index))) {
            index += UTF8StringPointable.charSize(data, index);
            tokenLength++;
        }
        int tokenCount = 1;
        if (tokenLength > 0 && !ignoreTokenCount) {
            // search if we got the same token before
            for (int i = 0; i < tokensStart.length(); ++i) {
                if (tokenLength == tokensLength.get(i)) {
                    int tokenStart = tokensStart.get(i);
                    tokenCount++; // assume we found it
                    int offset = 0;
                    int currLength = 0;
                    while (currLength < tokenLength) {
                        // case insensitive comparison
                        if (Character.toLowerCase(UTF8StringPointable.charAt(data, currentTokenStart + offset)) != Character
                                .toLowerCase(UTF8StringPointable.charAt(data, tokenStart + offset))) {
                            tokenCount--;
                            break;
                        }
                        offset += UTF8StringPointable.charSize(data, currentTokenStart + offset);
                        currLength++;
                    }
                }
            }
            // add the new token to the list of seen tokens
            tokensStart.add(currentTokenStart);
            tokensLength.add(tokenLength);
        }

        // set token
        token.reset(data, currentTokenStart, index, tokenLength, tokenCount);
    }
}